1. Field of the Invention
The present invention relates to structural elements for use as columns or beams for constructing wall and/or ceiling elements or as free-standing posts and masts with high buckling strength.
2. Statement of Related Art
Many structural elements comprising panel-supporting posts or columns are generally known, for example, as disclosed in German Published Applications Nos. 17 84 527 and 19 20 525, said elements being provided with parallel ribs forming grooves between them. Structural elements such as boards, panels, glass panes, etc. can be inserted into these grooves at different angles to produce adjustable walls, room partitions, show booths, and furniture for stores and homes.
In structural elements of this type, sections are also known which have a tubular cross-section, as shown for example in German Patents Nos. 29 31 026 and 3141807, and German Published Application No. 29 41 008. These tubular sections have a definite advantage over other sections in that they have greater stability with less material, primarily with regard to buckling strength. Although such known tubular sections, having outwardly-directed projections or ribs, star shaped, and usually T-shaped in cross-section, make it possible to fasten walls and the like in nearly all desired directions, they do have disadvantages, for example as regards their supporting and carrying properties. Since they have free-standing, outwardly-directed ribs, such ribs can break off easily in the radial direction under mechanical force. The supporting property of these sections therefore is unsatisfactory and they cannot be used for posts and supports subjected to high static stresses without the danger of failure. In addition, the free-standing ribs project from the supporting surface and present a risk of injury, especially when they are used as corner posts. To reduce the risk of injury with these known sections, the grooves which are not engaged must be covered up or masked by costly means, for example additional rubber sections, which provide a smooth external seal but do not correct the static weakness of the sections.
Another disadvantage of these known sections is that because of their design they are not suitable for use as girders and are not intended for such use. Another disadvantage is that these known sections have a large surface open to the exterior, which can lead to corrosion of the section and has a negative effect on static behavior.